linux-kernel - [PATCH v9 08/15] ACPI: processor_idle: Support polling state for LPI

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Message-Id: <20241107190818.522639-9-ankur.a.arora@oracle.com>
Date: Thu,  7 Nov 2024 11:08:11 -0800
From: Ankur Arora <ankur.a.arora@...cle.com>
To: linux-pm@...r.kernel.org, kvm@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-arch@...r.kernel.org
Cc: catalin.marinas@....com, will@...nel.org, tglx@...utronix.de,
        mingo@...hat.com, bp@...en8.de, dave.hansen@...ux.intel.com,
        x86@...nel.org, hpa@...or.com, pbonzini@...hat.com,
        vkuznets@...hat.com, rafael@...nel.org, daniel.lezcano@...aro.org,
        peterz@...radead.org, arnd@...db.de, lenb@...nel.org,
        mark.rutland@....com, harisokn@...zon.com, mtosatti@...hat.com,
        sudeep.holla@....com, cl@...two.org, maz@...nel.org,
        misono.tomohiro@...itsu.com, maobibo@...ngson.cn,
        zhenglifeng1@...wei.com, joao.m.martins@...cle.com,
        boris.ostrovsky@...cle.com, konrad.wilk@...cle.com
Subject: [PATCH v9 08/15] ACPI: processor_idle: Support polling state for LPI

From: Lifeng Zheng <zhenglifeng1@...wei.com>

Initialize an optional polling state besides LPI states.

Wrap up a new enter method to correctly reflect the actual entered state
when the polling state is enabled.

Signed-off-by: Lifeng Zheng <zhenglifeng1@...wei.com>
Reviewed-by: Jie Zhan <zhanjie9@...ilicon.com>
---
 drivers/acpi/processor_idle.c | 39 ++++++++++++++++++++++++++++++-----
 1 file changed, 34 insertions(+), 5 deletions(-)

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 44096406d65d..d154b5d77328 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -1194,20 +1194,46 @@ static int acpi_idle_lpi_enter(struct cpuidle_device *dev,
 	return -EINVAL;
 }
 
+/* To correctly reflect the entered state if the poll state is enabled. */
+static int acpi_idle_lpi_enter_with_poll_state(struct cpuidle_device *dev,
+			       struct cpuidle_driver *drv, int index)
+{
+	int entered_state;
+
+	if (unlikely(index < 1))
+		return -EINVAL;
+
+	entered_state = acpi_idle_lpi_enter(dev, drv, index - 1);
+	if (entered_state < 0)
+		return entered_state;
+
+	return entered_state + 1;
+}
+
 static int acpi_processor_setup_lpi_states(struct acpi_processor *pr)
 {
-	int i;
+	int i, count;
 	struct acpi_lpi_state *lpi;
 	struct cpuidle_state *state;
 	struct cpuidle_driver *drv = &acpi_idle_driver;
+	typeof(state->enter) enter_method;
 
 	if (!pr->flags.has_lpi)
 		return -EOPNOTSUPP;
 
+	if (IS_ENABLED(CONFIG_ARCH_HAS_OPTIMIZED_POLL)) {
+		cpuidle_poll_state_init(drv);
+		count = 1;
+		enter_method = acpi_idle_lpi_enter_with_poll_state;
+	} else {
+		count = 0;
+		enter_method = acpi_idle_lpi_enter;
+	}
+
 	for (i = 0; i < pr->power.count && i < CPUIDLE_STATE_MAX; i++) {
 		lpi = &pr->power.lpi_states[i];
 
-		state = &drv->states[i];
+		state = &drv->states[count];
 		snprintf(state->name, CPUIDLE_NAME_LEN, "LPI-%d", i);
 		strscpy(state->desc, lpi->desc, CPUIDLE_DESC_LEN);
 		state->exit_latency = lpi->wake_latency;
@@ -1215,11 +1241,14 @@ static int acpi_processor_setup_lpi_states(struct acpi_processor *pr)
 		state->flags |= arch_get_idle_state_flags(lpi->arch_flags);
 		if (i != 0 && lpi->entry_method == ACPI_CSTATE_FFH)
 			state->flags |= CPUIDLE_FLAG_RCU_IDLE;
-		state->enter = acpi_idle_lpi_enter;
-		drv->safe_state_index = i;
+		state->enter = enter_method;
+		drv->safe_state_index = count;
+		count++;
+		if (count == CPUIDLE_STATE_MAX)
+			break;
 	}
 
-	drv->state_count = i;
+	drv->state_count = count;
 
 	return 0;
 }
-- 
2.43.5